在Silverlight项目中，经常会根据需求的不同，提供不同的字符格式到客户端。这篇文章总结了目前Silverlight 4常用StringFormat绑定字符格式，方便大家在随后的开发中调用参考。
在Silverlight项目中，经常会根据需求的不同，提供不同的字符格式到客户端。这篇文章总结了目前Silverlight 4常用StringFormat绑定字符格式，方便大家在随后的开发中调用参考。
早期的格式转换方法
在 Silverlight 4 之前的版本，通常修改字符格式是通过实现 IValueConverter 接口，在 IValueConverter 接口中包含有两个方法：
1. Convert ， 在绑定源数据传送到客户端显示前，转换修改数据；
2. ConvertBack ，在目标数据传送到绑定源数据前，转换修改数据，该方法仅被用于 “TwoWay” 绑定模式；
例如，根据布尔型判断实现控件是否显示在客户端，下面是一个简单的转换代码，通过实现 IValueConverter ，判断控件 Visibility 属性值。
public class VisibilityConverter : IValueConverter { public object Convert(object value,Type targetType,object parameter,CultureInfo culture) { bool visibility = (bool)value; return visibility ? Visibility.Visible : Visibility.Collapsed; } public object ConvertBack(object value,Type targetType,object parameter,CultureInfo culture) { Visibility visibility = (Visibility)value; return (visibility == Visibility.Visible); } } Silverlight 4 的 StringFormat 属性
在 Silverlight 4 中，数据绑定 SDK 提供一个 “StringFormat” 的属性，该属性允许开发人员自由定义输出字符格式，例如， DataPicker 控件，该控件提供 SelectedDateFormat 属性，控制其输出格式 “ 短格式 ” 或 “ 长格式 ” 。
SelectedDateFormat="Short", “ 默认 ”
SelectedDateFormat="Long"
而如果需要输出 “April 01, 2011” 格式，则无法使用 SelectedDateFormat 控制其格式，这时可以使用 StringFormat 属性完成需求。
<toolkit:DatePicker SelectedDate="{Binding DemoDate,Mode=TwoWay, StringFormat='MMM d, yyyy'}" />
再例如，早期实现一段文字绑定信息需要按照以下格式操作：
<TextBlock Text=” 当前登录用户 : ”/>
<TextBlock Text=“{Binding Name}”/>
输出 : 当前登录用户 Jv9
在 Silverlight 4 中使用 StringFormat 属性，可以简单的实现如下 :
<TextBlock Text=“{Binding Name, StringFormat=’ 当前登录用户 : \{0\}’}”>
这样实现简单而又方便。
对于 StringFormat 属性的使用方法还有很多，下面使用实例演示常用的属性：
<Grid x:Name="LayoutRoot"><ScrollViewer x:Name="PageScrollViewer" Style="{StaticResource PageScrollViewerStyle}"><StackPanel Orientation="Horizontal"><StackPanel x:Name="ContentStackPanel"><TextBlock FontSize="16" TextWrapping="Wrap" Text="StringFormat 和字符串格式 " Margin="8"/><Border BorderBrush="LightGray" BorderThickness="1" Width="300" Margin="5" HorizontalAlignment="Left"><StackPanel Orientation="Vertical" Margin="5" ><TextBox x:Name="txtSource" Width="125" HorizontalAlignment="Left"/><TextBlock TextWrapping="Wrap" Text="StringFormat=' 正在输入 "\{0\}"." FontWeight="Bold" Margin="0,4,0,2"/><TextBlock Text="{Binding Text, ElementName=txtSource, StringFormat=' 正在输入 "\{0\}".'}" TextWrapping="Wrap" Margin="0,0,0,4"/><TextBlock TextWrapping="Wrap" Text="StringFormat=\{0\,20\}" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock Text="{Binding Text, ElementName=txtSource, StringFormat=\{0\,20\}}" TextWrapping="Wrap" Margin="0,0,0,4" /><TextBlock TextWrapping="Wrap" Text="StringFormat=\{0\,-20\}" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock Text="{Binding Text, ElementName=txtSource, StringFormat=\{0\,-20\}}" TextWrapping="Wrap" Margin="0,0,0,4"/></StackPanel></Border>
<StackPanel x:Name="DatePanel"><TextBlock Text="StringFormat 和日期格式 " Margin="8" FontSize="16" /><Border BorderBrush="LightGray" BorderThickness="1" Width="300" Margin="5" HorizontalAlignment="Left"><StackPanel DataContext="{StaticResource SampleDate}"><TextBlock TextWrapping="Wrap" Text="StringFormat=f" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=f}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=F" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=F}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=g" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=g}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=G" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=G}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=m" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=m}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=y" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=y}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=t" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=t}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=T" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=T}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=u" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=u}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=o" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=o}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=MM/dd/yy" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=MM/dd/yy}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat=MMMM dd\, yyyy g" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=MMMM dd\, yyyy g}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=hh:mm:ss.fff tt" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=hh:mm:ss.fff tt}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat=\{0:r\}" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat=\{0:r\}}" Margin="8,0" /><TextBlock TextWrapping="Wrap" Text="StringFormat='MMM d, yyyy'" FontWeight="Bold" Margin="0,4,0,2"/><TextBlock TextWrapping="Wrap" Text="{Binding CurrentDateTime, StringFormat='MMM d, yyyy'}" Margin="8,0" /></StackPanel></Border> </StackPanel></StackPanel><StackPanel Orientation="Vertical" ><TextBlock Text="StringFormat 和数字演示 " Margin="8" FontSize="16"/><Border BorderBrush="LightGray" BorderThickness="1" Width="300" Margin="5" HorizontalAlignment="Left"><StackPanel Orientation="Vertical" Margin="5"><Grid ><Grid.RowDefinitions><RowDefinition Height="Auto"/><RowDefinition Height="Auto"/></Grid.RowDefinitions><Grid.ColumnDefinitions><ColumnDefinition Width="Auto" MinWidth="18"/><ColumnDefinition/><ColumnDefinition Width="Auto" MinWidth="28"/></Grid.ColumnDefinitions><TextBlock Text="1" HorizontalAlignment="Left" d:LayoutOverrides="Height" /><TextBlock Text="100,000" d:LayoutOverrides="Width, Height" Grid.Column="2" Margin="0" /><Slider x:Name="BigNumSlider" Margin="0" d:LayoutOverrides="Height" Grid.ColumnSpan="3" Grid.Row="1" Maximum="100000" Minimum="1" Value="50000"/></Grid><TextBlock TextWrapping="Wrap" Text="StringFormat=c" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider, Mode=TwoWay, StringFormat=c}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat= 目前拥有现金 \{0:C0\}" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider, Mode=TwoWay, StringFormat= 目前拥有现金 \{0:C0\}}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat=e" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider, Mode=TwoWay, StringFormat=e}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat=\{0:E4\}" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider, Mode=TwoWay, StringFormat=\{0:E4\}}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat=n" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider, Mode=TwoWay, StringFormat=n}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat=\{0:N0\}" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider, Mode=TwoWay, StringFormat=\{0:N0\}}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat='###,###.##'" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider, Mode=TwoWay, StringFormat='###,###.##'}" Margin="8,0" /></StackPanel></Border>
<Border BorderBrush="LightGray" BorderThickness="1" Width="300" Margin="5" HorizontalAlignment="Left"><StackPanel Orientation="Vertical" Margin="5"><Grid ><Grid.RowDefinitions><RowDefinition Height="Auto"/><RowDefinition Height="Auto"/></Grid.RowDefinitions><Grid.ColumnDefinitions><ColumnDefinition Width="Auto" MinWidth="18"/><ColumnDefinition/><ColumnDefinition Width="Auto" MinWidth="28"/></Grid.ColumnDefinitions><TextBlock Text="-1" HorizontalAlignment="Left" d:LayoutOverrides="Height" /><TextBlock Text="1" d:LayoutOverrides="Width, Height" Grid.Column="2" Margin="0" /><Slider x:Name="BigNumSlider1" Margin="0" d:LayoutOverrides="Height" Grid.ColumnSpan="3" Grid.Row="1" Maximum="1" Minimum="-1" Value="0.2" LargeChange="0.1" SmallChange="0.01"/></Grid><TextBlock TextWrapping="Wrap" Text="StringFormat=n" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider1, Mode=TwoWay, StringFormat=n}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat=\{0:N4\}" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider1, Mode=TwoWay, StringFormat=\{0:N4\}}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat=p" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider1, Mode=TwoWay, StringFormat=p}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat=\{0:P0\}" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider1, Mode=TwoWay, StringFormat=\{0:P0\}}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat=\{0:E5\}" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider1, Mode=TwoWay, StringFormat=\{0:E5\}}" Margin="8,0"/><TextBlock TextWrapping="Wrap" Text="StringFormat=\{0:C3\}" FontWeight="Bold" Margin="0,4,0,2"/><TextBox TextWrapping="Wrap" Text="{Binding Value, ElementName=BigNumSlider1, Mode=TwoWay, StringFormat=\{0:C3\}}" Margin="8,0"/></StackPanel></Border></StackPanel></StackPanel></ScrollViewer></Grid>
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